U.S. patent application number 14/533335 was filed with the patent office on 2015-05-07 for image formation apparatus.
The applicant listed for this patent is Oki Data Corporation. Invention is credited to Shuichi FUJIKURA.
Application Number | 20150125172 14/533335 |
Document ID | / |
Family ID | 53007143 |
Filed Date | 2015-05-07 |
United States Patent
Application |
20150125172 |
Kind Code |
A1 |
FUJIKURA; Shuichi |
May 7, 2015 |
IMAGE FORMATION APPARATUS
Abstract
An image formation apparatus includes a fixing unit that heats a
medium having a developer image thereon while moving the medium to
fix a developer image onto the medium, a motor that provides the
fixing unit with a driving force to be used to move the medium, and
a controller that determines whether the driving force provided by
the motor is being transmitted to the fixing unit.
Inventors: |
FUJIKURA; Shuichi; (Tokyo,
JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Oki Data Corporation |
Tokyo |
|
JP |
|
|
Family ID: |
53007143 |
Appl. No.: |
14/533335 |
Filed: |
November 5, 2014 |
Current U.S.
Class: |
399/67 |
Current CPC
Class: |
G03G 21/1685 20130101;
G03G 15/2032 20130101; G03G 15/205 20130101; G03G 15/5012 20130101;
G03G 21/1647 20130101; G03G 15/2039 20130101; G03G 15/5004
20130101 |
Class at
Publication: |
399/67 |
International
Class: |
G03G 15/20 20060101
G03G015/20 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 7, 2013 |
JP |
2013-231232 |
Claims
1. An image formation apparatus, comprising: a fixing unit
configured to heat a medium while moving the medium to fix a
developer image on the medium; a motor configured to provide the
fixing unit with a driving force to be used to move the medium; and
a controller configured to determine whether the driving force
provided by the motor is being transmitted to the fixing unit.
2. The image formation apparatus according to claim 1, wherein the
controller is configured to determine whether the driving force
provided by the motor is being transmitted to the fixing unit when
the fixing unit is attached.
3. The image formation apparatus according to claim 1, wherein the
controller is configured to determine whether the driving force
provided by the motor is being transmitted to the fixing unit
before performing a warming-up of the fixing unit and, when the
driving force provided by the motor is not being transmitted to the
fixing unit, the controller does not perform the warming-up of the
fixing unit.
4. The image formation apparatus according to claim 1, wherein the
fixing unit includes: a fixing roller and a fixing back-up roller
which are configured to receive the driving force from the motor to
rotate in predetermined directions, and to heat the medium while
moving the medium: and an adjustment mechanism configured to adjust
a position of at least one of the fixing roller and fixing back-up
roller when the fixing roller and the fixing back-up roller are
rotated in directions reverse to the predetermined directions by
using the driving force provided by the motor, and the controller
is configured to control the motor so that the fixing roller and
the fixing back-up roller rotate in the reverse directions and to
determine whether the driving force provided by the motor is being
transmitted to the fixing unit based on whether the adjustment by
the adjustment mechanism is successful.
5. The image formation apparatus according to claim 4, wherein the
adjustment mechanism is configured to move the fixing back-up
roller to a previously determined position when the fixing roller
and fixing back-up roller are rotated in the reverse
directions.
6. The image formation apparatus according to claim 5, further
comprising: a position detection sensor configured to detect
whether the fixing back-up roller is moved to the previously
determined position, wherein the controller determines based on a
detection signal from the position detection sensor whether the
driving force provided by the motor is being transmitted to the
fixing unit.
7. The image formation apparatus according to claim 1, further
comprising: a power supply configured to switch between a first
mode in which electric power is supplied to the controller and a
second mode in which no electric power or less electric power than
that of the first mode is supplied to the controller; and a
sub-controller configured to be supplied with electric power from
the power supply during the second mode and detect whether the
fixing unit is detached, wherein if the sub-controller detects a
detachment of the fixing unit during the second mode, the
controller determines whether the driving force provided by the
motor is being transmitted to the fixing unit after the power
supply is switched from the second mode to the first mode.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority based on 35 USC 119 from
prior Japanese Patent Application No. 2013-231232 filed on Nov. 7,
2013, entitled "IMAGE FORMATION APPARATUS", the entire contents of
which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The disclosure relates to an image formation apparatus.
[0004] 2. Description of Related Art
[0005] There has been an image formation apparatus that detects
replacement of a consumable by detecting a change in the open/close
state of an upper cover and carries out a calibration concerning
the consumable whose replacement is detected (Patent Literature 1:
Japanese Patent Application Publication No. 2011-197417, for
example).
SUMMARY OF THE INVENTION
[0006] When a fixing unit used in an image formation apparatus is
detached and then attached again, a gear to drive the fixing unit
is sometimes not joined to a fixing roller of the fixing unit. In
this case, the fixing roller cannot rotate, and a medium remains in
the fixing unit, causing a printing failure.
[0007] Accordingly, an object of an embodiment of the invention is
to facilitate determining whether or not the transmission of a
driving force from the motor to the fixing unit is active.
[0008] An aspect of the invention is an image formation apparatus
that includes: a fixing unit that heats a medium having a developer
image thereon while moving the medium to fix the developer image
onto the medium; a motor that provides the fixing unit with a
driving force to be used to move the medium; and a controller that
determines whether the driving force provided by the motor is being
transmitted to the fixing unit.
[0009] According to the above-described aspect, it is possible to
facilitate determining whether or not the transmission of a driving
force from the motor to the fixing unit is active.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a cross-sectional diagram schematically
illustrating the configuration of the main portion of a printer as
an image formation apparatus according to Embodiment 1.
[0011] FIG. 2 is a block diagram schematically illustrating the
configuration of a control substrate in Embodiment 1.
[0012] FIG. 3 is a schematic diagram for explaining the relation of
connection between a main CPU, a sub-CPU, and a fixing unit in
Embodiment 1.
[0013] FIG. 4 is a cross-sectional diagram schematically
illustrating the configuration of the fixing unit in Embodiment
1.
[0014] FIG. 5 is a schematic diagram illustrating an example of an
adjustment mechanism in Embodiment 1.
[0015] FIG. 6 is a schematic diagram for explaining a transmission
mechanism in Embodiment 1.
[0016] FIG. 7 is a flowchart illustrating a process to monitor the
fixing unit in Embodiment 1.
DETAILED DESCRIPTION OF EMBODIMENTS
[0017] Descriptions are provided hereinbelow for embodiments based
on the drawings. In the respective drawings referenced herein, the
same constituents are designated by the same reference numerals and
duplicate explanation concerning the same constituents is omitted.
All of the drawings are provided to illustrate the respective
examples only.
Embodiment 1
Description of Configuration
[0018] FIG. 1 is a cross-sectional view schematically illustrating
the configuration of the main part of printer 100 as an image
formation apparatus according to Embodiment 1. Printer 100 includes
image formation units 101K, 101Y, 101M, and 101C (hereinafter,
referred to as image formation units 101 when it is unnecessary for
each particular unit to be differentiated), LED heads 102K, 102Y,
102M, and 102C (hereinafter, referred to as LED heads 102 when it
is unnecessary for each particular head to be differentiated),
transfer rollers 103K, 103Y, 103M, and 103C (hereinafter, referred
to as transfer rollers 103 when it is unnecessary for each
particular roller to be differentiated), paper feeding roller 104,
transport rollers 105A and 105B (hereinafter, referred to as
transport rollers 105 when it is unnecessary for each particular
roller to be differentiated), transport belt 106, driving roller
107, driven roller 108, delivery rollers 109A and 109B
(hereinafter, referred to as delivery rollers 109 when it is
unnecessary for each particular roller to be differentiated),
stacker 110, IN sensor 111, writing sensor 112, delivery sensor
113, and fixing unit 120.
[0019] Image formation unit 101 forms a toner image as a developer
image. For example, image formation unit 101 includes a
photoreceptor drum 101a as an image support body on which an
electrostatic latent image and a toner image are formed. LED head
102 is an exposure device configured to form the electrostatic
latent image on photoreceptor drum 101a by exposing photoreceptor
drum 101a. Transfer roller 103 is a transfer section configured to
transfer the toner image formed by image formation unit 101 onto
each medium PA such as paper.
[0020] Paper feed roller 104 supplies media PA to transport roller
105 one by one. Transport roller 105 puts each supplied medium PA
on transport belt 106. Transport belt 106 is an endless belt and is
laid over driving roller 107 and driven roller 108. Driving roller
107 rotates in a direction X as indicated by an arrow in FIG. 1 to
move transport belt 106. Driven roller 108 rotates along with the
movement of transport belt 106. Delivery roller 109 delivers medium
PA with toner fixed thereon by fixing unit 120 to stacker 110.
[0021] IN sensor 111 is configured to detect medium PA supplied
from paper feeding roller 104. Writing sensor 112 is a sensor
configured to detect the leading edge of medium PA for determining
the time to start writing. Delivery sensor 113 is configured to
detect medium PA discharged from fixing unit 120. Delivery sensor
113 thereby also functions as a sensor to monitor whether medium PA
is wound around fixing unit 120.
[0022] Fixing unit 120 is configured to fix the toner image on
medium PA by heating medium PA while moving medium PA. For example,
fixing unit 120 includes fixing roller 121 and fixing back-up
roller 122 which heat medium PA while moving medium PA. Fixing
roller 121 includes a heat generator such as a halogen lamp inside
and is heated to a temperature of about 200.degree. C. to heat
medium PA, for example. Fixing back-up roller 122 presses medium PA
against fixing roller 121. When fixing roller 121 and fixing
back-up roller 122 rotate in predetermined directions as indicated
by the arrows in FIG. 1, medium PA moves in the previously
determined direction to be discharged from fixing unit 120. Fixing
unit 120 has such a structure that a user or a maintenance worker
can easily detach fixing unit 120 as a unit of maintenance.
[0023] Printer 100 includes motors to rotate rollers, rollers which
are provided at intervals not more than the minimum medium distance
on the transport path; and clutches used to turn on or off power
transmission to the rollers on the transport path, which are not
illustrated in FIG. 1.
[0024] FIG. 2 is a block diagram schematically illustrating the
configuration of control substrate 130 as a controller of printer
100. Control substrate 130 includes: main CPU 131 as a main
controller; sub-CPU 132 as a sub-controller; ROM 133 as a storage
unit; image processing LSI 134 as an image processing unit
controlling LED heads 102; and motor driver 135 as a motor
controller to control motor 150. In Embodiment 1, main CPU 131,
image processing LSI 134, and motor driver 135 constitute a
controller controlling the entire process of printer 100. Motor 150
is configured to provide the driving force used to move medium PA
to fixing unit 120.
[0025] Main CPU 131 operates according to a program written in ROM
133 and controls the major processing in printer 100. In Embodiment
1, in particular, main CPU 131 determines whether the driving force
provided by motor 150 is being transmitted to fixing unit 120. For
example, main CPU 131 determines whether fixing unit 120 is
attached based on a voltage value detected by thermistor 123 as a
fixing unit detector (a fixing unit detection sensor) provided for
fixing unit 120. To be specific, when the voltage value detected by
thermistor 123 is smaller than a previously determined threshold
value, main CPU 131 determines that fixing unit 120 is detached.
When fixing unit 120 is attached, main CPU 131 controls motor 150
so that motor 150 provides a driving force to fixing unit 120 for
an adjustment operation that adjusts the position of at least one
of fixing roller 121 and fixing back-up roller 122. When the
adjustment operation is successful, in other words, when it is
confirmed that the driving force from motor 150 is being
transmitted to fixing roller 121 and fixing back-up roller 122,
main CPU 131 performs an initialization (warming up) of fixing unit
120. When the adjustment operation is unsuccessful, main CPU 131
does not perform the initialization of fixing unit 120. Main CPU
131 determines, based on a detection signal from position detection
sensor 140, whether the adjustment operation is successful. The
adjustment operation is descried later.
[0026] Sub-CPU 132 assists in the processing of main CPU 131. In
Embodiment 1, in particular, when main CPU 131 is not supplied with
electric power from power supply 160, or when electric power
supplied from power supply 160 to main CPU 131 is limited, sub-CPU
132 is supplied with electric power from power supply 160 and
detects whether fixing unit 120 is detached. For example, sub-CPU
132 monitors the power switch and a sensor previously determined
when power supply 160 of printer 100 is in OFF mode or is in a
network stand-by mode (in the sleep mode). In particular, sub-CPU
132 detects whether fixing unit 120 is detached at the OFF or sleep
mode of power supply 160. To be specific, as illustrated in FIG. 3,
sub-CPU 132 is connected to signal line 170 connected to fixing
unit 120 through drawer connector 124. Fixing unit 120 is always
subjected to a voltage from power supply 160 through signal line
171. Fixing unit 120 returns the voltage applied through signal
line 171 to signal line 170 through signal line 172. When fixing
unit 120 is detached, the connection of drawer connector 124 is
also disconnected, and sub-CPU 132 is not subjected to a voltage
from signal line 170. When not subjected to the voltage from signal
line 170, sub-CPU 132 sets to L, a notification signal for main CPU
131 to notify main CPU 131 of the detachment of fixing unit 120.
Sub-CPU 132 continues the notification until receiving a clear
command from main CPU 131 through a clear signal.
[0027] Back to the description of FIG. 2, image processing LSI 134
assists in the image processing of main CPU 131. This is because
the image processing cannot be performed at a speed high enough
only by main CPU 131. Motor driver 135 controls motor 150 in
accordance with an instruction from main CPU 131.
[0028] Power supply 160 supplies electric power to each section of
printer 100. Power supply 160 includes main power supply 161 and
sub-power supply 162, for example. Main power supply 161 supplies
power to each section of printer 100 during the normal mode. In the
example illustrated in FIG. 2, main power supply 161 supplies
electric power to LED head 102, fixing unit 120, main CPU 131, ROM
133, image processing LSI 134, motor driver 135, position detection
sensor 140, and motor 150. Sub-power supply 162 is configured to
supply electric power to previously determined sections of printer
100 during the sleep and OFF modes. In the example illustrated in
FIG. 2, sub-power supply 162 supplies electric power to sub-CPU 132
and drawer connector 124.
[0029] The normal mode is a mode in which electric power is
supplied to at least heater 125 of fixing unit 120 and motor 150.
In Embodiment 1, electric power is also supplied to main CPU 131,
which consumes a large amount of power, during the normal mode. The
sleep mode is a mode in which electric power is supplied to only
the previously determined sections of printer 100 so that the power
consumption is less than that of the normal mode. In the sleep
mode, electric power is not supplied to at least one of heater 125
and motor 150. In Embodiment 1, in the sleep mode, electric power
is not supplied to main CPU 131, heater 125, and motor 150 so that
the power consumption is not more than 4 W. Main power supply 161
may be configured to supply electric power to only a predetermined
section of main CPU 131 during the sleep mode. The OFF mode is a
mode in which power supply 160 is off. In Embodiment 1, electric
power is not supplied to main CPU 131, heater 125, and motor 150 so
that the power consumption during the OFF mode is not more than 1
W, and only the power switch and minimum required sensors, such as
a sensor detecting the user's touch to raise an alarm, are
monitored. Herein, the normal mode is included in a first mode in
which main CPU 131 is supplied with electric power from main power
supply 161. The sleep and OFF modes are included in a second mode
in which main CPU 131 is not supplied with electric power from main
power supply 161. Main CPU 131 may be supplied with electric power
from sub-power supply 162 also in the sleep and OFF modes (the
second mode). However, the electric power supplied to main CPU 131
in the sleep and OFF modes is limited to less than that in the
normal mode (the first mode). In power supply 160, main power
supply 161 and sub-power supply 162 are switched under the control
of main CPU 131 and sub-CPU 132. This can change the power supply
mode described above.
[0030] Main CPU 131 controls a belt, a motor to transport print
media, and a motor or a clutch driver to drive a clutch as a
driving system (not illustrated in FIG. 2).
[0031] FIG. 4 is a cross-sectional diagram schematically
illustrating the configuration of fixing unit 120 in Embodiment 1.
Arrow Y in FIG. 4 indicates the direction that media PA are
transported. Fixing unit 120 includes fixing roller 121, fixing
back-up roller 122, upper thermistor 123A, lower thermistor 123B,
and heater 125.
[0032] Heater 125 is a halogen heater which receives electric power
from power supply 160 to heat fixing roller 121 under the control
of main CPU 131. Fixing roller 121 receives and accumulates the
heat from heater 125 and adds heat to the toner transferred to
medium PA. Upper thermistor 123A detects the temperature of fixing
roller 121. Lower thermistor 123B detects the temperature of fixing
back-up roller 122. Upper and lower thermistors 123A and 123B
constitute the thermistor 123 illustrated in FIG. 2.
[0033] Fixing roller 121 and fixing back-up roller 122 include
aluminum or iron tubes 121a and 121a inside, respectively. The
outer portions thereof are composed of rubber members 121a and 122b
as elastic members to increase the adhesion to the media,
respectively. Fixing unit 120 is provided with a spring which
energizes at least one of fixing roller 121 and fixing back-up
roller 122 so as to compress rubber members 121b and 122b.
[0034] When a medium constructed of layers of paper like an
envelope is transported to fixing unit 120 configured as described
above, wrinkles occur because fixing roller 121 and fixing back-up
roller 122 rotate at different speeds and the like. In order to
prevent the occurrence of wrinkles during printing on a thick
medium such as an envelope, printer 100 includes an adjustment
mechanism (an adjustment unit) configured to reduce the pressing
force of fixing roller 121 against fixing back-up roller 122.
[0035] FIG. 5 is a schematic diagram illustrating an example of the
adjustment mechanism in Embodiment 1. Adjustment mechanism 180
includes cam 181, first axle 182, arm 183, second axle 184, and
lever 185. Cam 181 rotates about first axle 182. Arm 183 rotates
about second axle 184. An end of arm 183 is in contact with cam
181. Cam 181 varies in thickness between the outer surface and
first axle 182. Accordingly, when cam 181 rotates, the contact
point with arm 183 shifts from the thin portion of cam 181 to the
thick portion, and arm 183 thereby rotates about second axle 184 in
the direction of arrow Z in FIG. 5.
[0036] The other end of arm 183 is attached to axle 122c of fixing
back-up roller 122. Accordingly, fixing back-up roller 122 is moved
in the direction of arrow Z when arm 183 rotates in the direction
of arrow Z. Adjustment mechanism 180 thus configured is attached to
each end of fixing back-up roller 122. When fixing back-up roller
122 is moved in the direction of arrow Z, fixing roller 121 moves
away from fixing back-up roller 122, thus reducing the pressing
force of fixing roller 121 against fixing back-up roller 122.
[0037] Lever 185 is attached to arm 183, and position detection
sensor 140 detects a change in the position of lever 185. Position
detection sensor 140 is an optical sensor including a light
emitting unit and a light receiving unit, which are not shown, for
example. When arm 183 is moved in direction Z, that is, when fixing
back-up roller 122 is moved to the position previously determined,
for example, the light from the light emitting unit is blocked by
lever 185. Position detection sensor 140 thereby detects that
fixing back-up roller 122 is moved to the position previously
determined, that is, detects that adjustment mechanism 180 operates
normally.
[0038] Cam 181 is rotated through a transmission mechanism
including at least one gear by driving force from motor 150 as the
driving source which rotates fixing roller 121 and fixing back-up
roller 122.
[0039] FIG. 6 is a schematic view for explaining a transmission
mechanism for transmitting a driving force from motor 150 to cam
181, fixing roller 121, and fixing back-up roller 122. Transmission
mechanism 151 includes first gear 152, second gear 153, fixing
roller gear 154, one-way gear 155, third gear 156, and cam gear
157.
[0040] Motor gear 150a rotated by motor 150 is engaged with first
gear 152. First gear 152 is engaged with second gear 153, and
second gear 153 is engaged with fixing roller gear 154 connected to
fixing roller 121. When motor gear 150a is rotated by motor 150, a
driving force is transmitted through first and second gears 152 and
153 to fixing roller gear 154 rotating fixing roller 121.
[0041] Rotary shaft 153a, rotated together with second gear 153, is
provided with a one-way gear 155. One-way gear 155 includes a
clutch inside. One-way gear 155 is configured not to rotate when
rotary shaft 153a rotates in a normal direction, or in other words,
when fixing roller 121 rotates in such a direction that media PA is
delivered, but to rotate only when rotary shaft 153a rotates in the
reverse direction. One-way gear 155 is engaged with third gear 156,
and third gear 156 is engaged with cam gear 157 connected to first
shaft 182 to rotate cam 181. Accordingly, when motor gear 150a is
rotated in the reverse direction by motor 150, cam 180 is rotated
by one-way gear 155, third gear 156, and cam gear 157, and arm 183
is moved in the direction Z. Fixing back-up roller 122 is moved to
the position previously determined, thus reducing the pressing
force of fixing roller 121 against fixing back-up roller 122. When
adjustment mechanism 180 operates normally, the driving force from
motor 150 is transmitted to transmission mechanism 151 described
above, or in other words, the driving force from motor 150 is
transmitted to fixing roller 121 and fixing back-up roller 122.
Generally, gears cannot be rotated in the reverse direction if they
are not engaged securely. Therefore, it can be confirmed that the
gears are securely engaged with each other by operating motor 150
in the reverse direction to confirm that the driving force from
motor 150 is being transmitted to transmission mechanism 151.
[0042] In Embodiment 1, all or a part of transmission mechanism 151
is provided for fixing unit 120. When fixing unit 120 is detached,
all or a part of transmission mechanism 151 is detached together
with fixing unit 120. Herein, a part of transmission mechanism 151
includes second gear 153, fixing roller gear 154, one-way gear 155,
third gear 156, and cam gear 157, for example.
(Explanation of Operation)
[0043] Hereinafter, a description is given of the operation of
printer 100 in Embodiment 1. Printer 100 is connected to a host by
a wired or wireless communication link (not illustrated). Print
data is transferred from the host to printer 100. Upon receiving an
instruction to print, main CPU 131 rotates paper feeding roller 104
to feed one medium PA to transport roller 105.
[0044] Image formation unit 101 starts the rotation of the rollers
substantially at the same time as the start of the paper feed.
Along with the start of the rotation, driving roller 107 rotates,
and transport belt 106 also starts moving at a constant speed. Each
medium PA skews when separated by paper feeding roller 104. Medium
PA hits transport roller 105 which is not rotating so that the skew
thereof is removed.
[0045] When medium PA hits transport roller 105, transport roller
105 is connected to power by the clutch so to rotate. Medium PA is
further transported and turns ON write sensor 112. Within a certain
period of time after write sensor 112 is turned ON, LED head 102K
starts an exposure to form an electrostatic latent image on
photoreceptor drum 101a. Development roller 101b supplies toner to
the formed electrostatic latent image to form a toner image on
photoreceptor drum 101a. The toner image is transferred to medium
PA by applying a voltage of about +3000 V to transfer roller 103K.
In a similar manner, an exposure and transfer are sequentially
performed for images of the other colors. When the transfer to
medium PA is finished, medium PA is heated and pressurized between
fixing roller 121 heated to about 200.degree. C. and fixing back-up
roller 122, so that the toner image is fixed on medium PA. After
the fixing, medium PA turns ON delivery sensor 113 and then is
delivered to stacker 110 by delivery roller 109.
[0046] In some cases, the driving force from motor 150 is not
transmitted to fixing roller 121 and fixing back-up roller 122
because of a disconnection of the gears that drive fixing roller
121 and fixing back-up roller 122 or the like. In such a case,
medium PA enters fixing unit 120, in which the surface temperature
of fixing roller 121 is maintained at 200.degree. C., and the
temperature control is carried out with medium PA staying in fixing
unit 120. Normally, medium PA is heated while moving, and the
surface of medium PA is heated to about 100.degree. C. However,
medium PA is heated to about 200.degree. C. when medium PA stays in
fixing unit 120. When medium PA is paper, medium PA turns yellow.
When medium PA is made of a low heat resistant film, medium PA
melts and sticks to fixing roller 121 and fixing back-up roller
122. The film sticking to fixing roller 121 and fixing back-up
roller 122 prevents thermistor 123 from detecting the correct
temperature, thus causing a printing failure.
[0047] In Embodiment 1, when fixing unit 120 is detached, it is
confirmed by using adjustment mechanism 180 described above by
determining whether the driving force from motor 150 is being
transmitted to fixing roller 121 and fixing back-up roller 122.
Specifically, main CPU 131 activates adjustment mechanism 180. When
position detection sensor 140 detects a movement of fixing back-up
roller 122, main CPU 131 determines that fixing unit 120 is
normally attached and goes to the normal printing operation. On the
other hand, when position detection sensor 140 cannot detect
movement of fixing back-up roller 122, main CPU 131 notifies the
user of an error and does not go to the printing operation. In
Embodiment 1, the adjustment operation is carried out by main CPU
131 that operates motor 150 in the reverse direction.
[0048] Detachment of fixing unit 120 is monitored by main CPU 131
and sub-CPU 132. Sub-CPU 132 is supplied with electric power even
when power supply 160 is in the OFF mode and sleep mode and
therefore monitors for detachment of fixing unit 120 in the OFF
mode and sleep mode.
[0049] FIG. 7 is a flowchart illustrating a process of monitoring
fixing unit 120 in Embodiment 1. The flowchart illustrated in FIG.
7 is started when power supply 160 is turned on (returns to the
normal mode from the OFF mode), when power supply 160 returns from
the sleep mode to the normal mode, or when the cover of printer 100
is closed. In these cases, registers (not illustrated) are set to
initial values, and a judgment routine for fixing unit 120 is
started.
[0050] Main CPU 131 determines whether fixing unit 120 is attached
to printer 100 (S10). Main CPU 131 performs the determination by
using a voltage detected by thermistor 123, for example. When
fixing unit 120 is not attached to printer 100 (No in S10), the
process goes to step S11. When fixing unit 120 is attached to
printer 100 (Yes in S10), the process goes to step S12.
[0051] In step S11, main CPU 131 turns on a no-heater bit which is
reserved in memory 131a as a work memory. In this process, main CPU
131 notifies the user by displaying an error screen on a display
section (not illustrated) or by another means and then returns the
process to step S10. The no-heater bit indicates information on
whether fixing unit 120 is detached from printer 100 when power
supply 160 of printer 100 is in the normal mode.
[0052] In step S12, main CPU 131 determines whether there is a
record of fixing unit 120 being detached. Main CPU 131 determines
that the record of fixing unit 120 being detached exists when the
notification signal from sub-CPU is L and determines that the
record of fixing unit 120 being detached does not exist when the
notification signal from sub-CPU 132 is H. Herein, the existence of
the record of fixing unit 120 being detached represents that fixing
unit 120 is detached from printer 100 at least when power supply
160 of printer 100 is in the OFF mode or sleep mode. When the
record of fixing unit 120 being detached does not exist (No in
S12), the process goes to step S13. When the record of fixing unit
120 being detached exists (Yes in S12), the process goes to step
S14.
[0053] In step S13, main CPU 131 confirms whether the no-heater bit
in memory 131a is on. When the no-heater bit is on (Yes in S13),
the process goes to step S14. When the no-heater bit is off (No in
S13), the process goes to step S17.
[0054] In step S14, main CPU 131 operates motor 150 in the reverse
direction for an adjustment operation by adjustment mechanism 180.
Main CPU 131 then determines whether the adjustment operation is
successful (S15). For example, main CPU 131 determines that the
adjustment operation is successful when receiving the detection
signal from position detection sensor 140 within a predetermined
period of time after the adjustment operation is started. Main CPU
131 determines that the adjustment operation is unsuccessful when
not receiving the detection signal from position detection sensor
140 within the predetermined period of time after the adjustment
operation is started. When the adjustment operation is unsuccessful
(No in S15), the process goes to step S16. When the adjustment
operation is successful (Yes in S15), the process goes to step
S17.
[0055] In step S16, main CPU 131 performs error processing. The
error processing includes notifying the user by displaying an error
screen in a display section (not illustrated), stopping motors in
operation, and the like, for example.
[0056] In step 17, main CPU 131 starts an initialization (warming
up) of printer 100, especially, fixing unit 120. The initialization
includes an energization of heater 125. Moreover, main CPU 131
sends the clear signal to sub-CPU 132 and turns off the no-heater
bit in memory 131a.
[0057] As described above, according to Embodiment 1, when fixing
unit 120 is detached and then attached, it is confirmed whether the
driving force from motor 150 is being transmitted to fixing unit
120 before starting the warming up of fixing unit 120. Accordingly,
the operations of fixing roller 121 and fixing back-up roller 122
of fixing unit 120 can be checked before an energization of heater
125 of fixing unit 120, thus ensuring safety. In Embodiment 1, the
operation check of fixing unit 120 is not performed when fixing
unit 120 has not been detached. In this case, it is possible to
shorten the warm-up time of fixing unit 120 and to restart the
printing within a shorter time period.
[0058] As described above, Embodiment 1 is described by using
printer 100 as the image formation apparatus as an example. In
addition to printer 100, the invention is applicable to image
formation apparatuses such as electrophotographic copiers,
facsimiles, and multi function peripherals (MFPs) including the
functions of printers, copiers, and facsimiles.
[0059] The invention includes other embodiments in addition to the
above-described embodiments without departing from the spirit of
the invention. The embodiments are to be considered in all respects
as illustrative, and not restrictive. The scope of the invention is
indicated by the appended claims rather than by the foregoing
description. Hence, all configurations including the meaning and
range within equivalent arrangements of the claims are intended to
be embraced in the invention.
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